Efficient ammonium removal from aquatic environments by Acinetobacter calcoaceticus STB1 immobilized on an electrospun cellulose acetate nanofibrous web

Cataloged from PDF version of article.A novel biocomposite material was developed by immobilizing an ammonia-oxidizing bacterial strain, Acinetobacter calcoaceticus STB1, on an electrospun porous cellulose acetate (CA) nanofibrous web. Ammonium removal characteristics of the STB1 immobilized CA nanofibrous web were determined at varying initial ammonium concentrations, and removal rates of 100%, 98.5% and 72% were observed within 48 h for 50 mg L-1, 100 mg L-1 and 200 mg L-1 samples, respectively. Most of the ammonia is inferred to be converted into nitrogen or is accumulated as bacterial biomass, as only trace amounts of ammonium were converted into nitrite or nitrate. Reusability test results indicate that, at an initial ammonium concentration of 100 mg L-1, bacteria-immobilized CA nanofibrous webs can be reused for at least 5 cycles. SEM images of the STB1/CA nanofibrous web after five cycles of reuse and rigorous washing demonstrate that bacterial biofilms strongly adhere to nanofiber surfaces

Effects of edentulism in obstructive sleep apnea syndrome

Objectives: The purpose of this study was to investigate the effects of edentulism in obstructive sleep apnea syndrome (OSAS) patients.Materials and Methods: The study patients’ were selected from the Gaziantep University Sleep Clinic and Orthodontic Department archives between the years of 2009 and 2011. Study groups were determined according to age and edentulism, and the overall study population consisted of 42 (21 male, 21 female) OSAS patients. Data from 14 edentulous (Group I), 14 older dentate (Group II), and 14 middle‑aged dentate OSAS patients (Group III) were compared in this study. Polysomnographic parameters, which were measured and analyzed included: Sleep time, sleep efficiency, sleep stage 1, sleep stage 2, sleep stage 3, percentage of rapid eye movement sleep, apnea‑hypopnea index, oxygen saturation and arousal index. The Kruskal–Wallis and Mann–Whitney U statistical tests were used for comparing the differences between the three groups and subgroups.Results: Sleep time parameters showed significant differences between the groups (P < 0.05). Differences occurred between Group I and Group III in the sleep time parameter (P < 0.05), while the edentulous subjects showed lower mean sleep time values when compared to the older and middle‑aged dentate groups.Conclusion: According to our results, edentulism may not impact polysomnography parameters, with the exception of the sleep time parameter. Important attention should be given to edentulous individuals during sleep with their dentures to prevent OSAS complications. The use of dentures may prevent or protect patients from the predisposing factors of OSAS.Keywords: Dentures, edentulous, obstructive sleep apnea syndrome, polysomnograph

Multifunctional electrospun polymeric nanofibrous mats for catalytic reduction, photocatalysis and sensing

Fabrication and decoration of flexible Nylon 6,6 polymeric nanofibrous mats for production of multifunctional electrospun material was accomplished via visible light-emitting surface-protected silicon quantum dots (Si QD), ZnO nanoparticles (ZnO NP) and Pd nanocubes (Pd NC). UV-range light was utilized for Si QD production and, after hydrolysis/condensation together with nucleation and growth reactions, amine-modified, fluorescent Si QD were obtained. Additionally, available molecular groups on the Si QD coated onto the polymeric nanofibrous mats provided further attachment of metal oxide and metal NP for various catalytic purposes. Analytical investigations showed that visible-light emission could be maintained on the Nylon 6,6 mats for trinitrotoluene (TNT) sensing. Also, due to consecutive NP decoration, multifunctional, polymeric, flexible nanofibrous mats were obtained. Experiments revealed that fabricated multifunctional mats could reduce molecules such as paranitrophenol effectively or decompose waste dyes such as methylene blue via photocatalytic experiments, and sense the pollutant TNT in aqueous solutions as an all-in-one concept. © 2017 The Royal Society of Chemistry

Fluorescent Si QD decoration onto a flexible polymeric electrospun nanofibrous mat for the colorimetric sensing of TNT

UV range light was used for the facile, effective and large-scale synthesis of visible light emitting, surface-protected silicon quantum dots (Si QDs) starting from an amine-functionalized alkoxy silane precursor. Within mild and easy hydrolysis/condensation environments, the use of an amine-functionalized precursor together with a reducing agent resulted in a bright visible green light that could be used for fluorescent analytical detection systems. Visible light emitting Si QDs were investigated and it was found that their emission character depends on the illumination time, hydrolysis/condensation conditions and pretreatments for the silane coupling agents. A Nylon 6,6 electrospun nanofibrous mat was selected as a substrate for decoration by the Si QDs in order to fabricate a flexible and free-standing polymeric nanofibrous mat posessing a visible light emitting character so that it could act as a visible colorimetric sensor. The visible light emitting Si QDs were decorated onto the Nylon 6,6 nanofibrous mats via covering the surfaces as a ‘nanodress’ by a simple impregnation/dip-coating and heat-curing methods. The analytical results revealed that the Si QDs decorated flexible polymeric nanofibrous mats could be utilized for colorimetric trinitrotoluene (TNT) detection in low concentrations. © The Royal Society of Chemistry

Superhydrophobic, Hybrid, Electrospun Cellulose Acetate Nanofibrous Mats for Oil/Water Separation by Tailored Surface Modification

Electrospun cellulose acetate nanofibers (CA-NF) have been modified with perfluoro alkoxysilanes (FS/CA-NF) for tailoring their chemical and physical features aiming oil-water separation purposes. Strikingly, hybrid FS/CA-NF showed that perfluoro groups are rigidly positioned on the outer surface of the nanofibers providing superhydrophobic characteristic with a water contact angle of ∼155°. Detailed analysis showed that hydrolysis/condensation reactions led to the modification of the acetylated β(1 → 4) linked d-glucose chains of CA transforming it into a superhydrophobic nanofibrous mat. Analytical data have revealed that CA-NF surfaces can be selectively controlled for fabricating the durable, robust and water resistant hybrid electrospun nanofibrous mat. The -OH groups available on the CA structure allowed the basic sol-gel reactions started by the reactive FS hybrid precursor system which can be monitored by spectroscopic analysis. Since alkoxysilane groups on the perfluoro silane compound are capable of reacting for condensation together with the CA, superhydrophobic nanofibrous mat is obtained via electrospinning. This structural modification led to the facile fabrication of the novel oil/water nanofibrous separator which functions effectively demonstrated by hexane/oil and water separation experiments. Perfluoro groups consequently modified the hydrophilic CA nanofibers into superhydrophobic character and therefore FS/CA-NF could be quite practical for future applications like water/oil separators, as well as self-cleaning or water resistant nanofibrous structures. © 2016 American Chemical Society

Reusable and Flexible Heterogeneous Catalyst for Reduction of TNT by Pd Nanocube Decorated ZnO Nanolayers onto Electrospun Polymeric Nanofibers

An effective method for the fabrication of well designed nanocomposite for the catalytic reduction of 2,4,6-trinitrotoluene (TNT) was developed. Here, cubic palladium (Pd) nanoparticles were utilized for enhancing the interface properties, attachment quality, catalytic yield and stability after the catalysis reactions. Ligand controlled facet growth by the Br- anions during thermal decomposition of the palladium-precursor resulted with cubic shaped average ∼13 nm palladium nanocubes (Pd NC). The anisotropic Pd NC were utilized to decorate the surface of the zinc oxide (ZnO) nanolayers deposited by atomic layer deposition (ALD) technique on the electrospun polyacrylonitrile (PAN) nanofibers. Due to the polymeric nature of the electrospun PAN nanofibers, Pd NC decorated nanoweb is highly flexible and has a high surface area. For the sustainable Pd NC decoration on the ZnO surfaces coated on PAN nanofibers, anchor points were formed by the functional thiol groups which can facilitate the Pd NC attachment and stability on the ZnO surface. The -OH and alkyl thiol groups obtained via sol-gel reactions positioned on the ZnO layer providing a better interface between ZnO and Pd NC which cannot be obtained by pristine PAN nanofibers. Additionally, due to the increased surface interaction, geometrical positioning on fibers for a better intermediate complex formation and stability via soft-soft interaction, Pd NC decorated flexible polymeric electrospun nanoweb provided enhanced catalytic reduction of TNT in aqueous medium. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

Singlet Oxygen Generation with Chemical Excitation of an Erythrosine-Luminol Conjugate

Chemical generation of singlet oxygen under biologically relevant conditions is very important, considering the role played by singlet oxygen in cancer therapeutics. We now demonstrate that a luminol derivative can be chemically excited and transfer the excitation energy to the covalently attached photosensitizer derived from erythrosin. A photosensitizer module, when excited in this manner, can generate singlet oxygen in solution. As hydrogen peroxide is present in a relatively high concentration in cancer cells, singlet oxygen generation through chemical excitation may evolve into an important therapeutic approach. © 2017 American Chemical Society

Pd nanocube decoration onto flexible nanofibrous mats of core-shell polymer-ZnO nanofibers for visible light photocatalysis

Plasmonic enhancement for electron-hole separation efficiency and visible light photocatalysis was achieved by Pd nanocube decoration on a ZnO nanolayer coated onto electrospun polymeric (polyacrylonitrile (PAN)) nanofibers. Since exciton formation and sustainable electron-hole separation have a vital importance for realizing better solar energy in photovoltaic and photocatalytic devices, we achieved visible light photocatalysis by Pd nanocube decoration onto well designed core-shell nanofibers of ZnO@PAN-NF. By controlling the cubic Pd nanoparticle size and the thickness of the crystalline ZnO nanolayer deposited onto electrospun PAN nanofibers via atomic layer deposition (ALD), defect mediated visible light photocatalysis efficiency can be increased. By utilizing nanofabrication techniques such as thermal decomposition, electrospinning and ALD, this fabricated template became an efficient, defect mediated, Pd nanocube plasmon enhanced photocatalytic system. Due to the enhanced contact features of the Pd nanocubes, an increase was observed for the visible light photocatalytic activity of the flexible and nanofibrous mat of Pd@ZnO@PAN-NF. © 2017 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique

Flexible organic-inorganic core-shell nanofibers by electrospinning and atomic layer deposition

Organic-inorganic core-shell nanofibers were fabricated by combining electrospinning and atomic layer deposition (ALD). In the first step, nylon66 (polymeric organic core) nanofibers having different average fiber diameters (∼100 nm, ∼250 nm and ∼650 nm) were electrospun by using different solvent systems and polymer concentrations. In the second step, uniform and conformal layer of zinc oxide (ZnO) (inorganic shell) with precise thickness (∼90 nm) and composition on the round surface of the nylon nanofibers were deposited by ALD. The core-shell nylon66-ZnO nanofibers have shown unique properties such as structural flexibility due to the polymeric core and photocatalytic activity due to the ZnO shell layer

Bilkent news portal: A personalizaba system with new event detection and tracking capabilities

[No abstract available